This invention relates to carbon black floc that is associated with wet-process phosphoric acid. In one of its aspects this invention relates to removal of carbon black floc associated with wet-process phosphoric acid. In another of its aspects this invention relates to the production of liquid fertilizer by the neutralization of wet-process phosphoric acid. In still another aspect this invention relates to producing fertilizer of clear or near-clear appearance from wet-process phosphoric acid.
In the process of reacting calcium phosphate rock with sulfuric acid and the manufacture of wet-process phosphoric acid the organic matter is carried over in the phosphoric acid. This results in a concentration of carbon floc both in the wet-process phosphoric acid and in products made from reacting the wet-process phosphoric acid such as liquid fertilizer which is made by neutralizing the wet-process phosphoric acid with ammonia. Unfortunately, even a very low concentration of the carbon floc such as the amount 0.4 weight percent concentration often found in liquid fertilizer, is sufficient to give both an objectionable color and to cause problems associated with settling of floc during periods of storage.
It is therefore an object of this invention to provide a method for removing carbon floc from wet-process phosphoric acid. It is another object of this invention to provide a method for removing carbon floc from liquid fertilizer produced by neutralization of wet-process phosphoric acid with ammonia. It is another object of this invention to provide a method for removing carbon floc as liquid fertilizer is being produced from wet-process phosphoric acid. It is still another object of this invention to provide liquid fertilizer of clear or near-clear appearance.
Other aspects, objects and the various advantages of this invention will become apparent upon reading the specification and the appended claims.